Polychlorinated azoxy and azobenzenes are potential environmental contaminants resulting from industrial synthesis and agricultural application of chloroanilide herbicides. In order to assess the potential health hazards associated with these compounds, in vivo and in vitro experiments will be conducted. After developing the essential chemical tools, male Sprague-Dawley rats will be intubated with varying doses of 3,4,3',4'-tetrachloroazobenzene (TCAB) and/or 3,4,3'4'-tetrachloroazoxybenzene (TCAOB). Premortem and postmortem examinations on these animals will permit evaluation of the toxicity (specifically, structural and functional alterations), target organ(s), tissue distribution, and metabolic fate of TCAB and TCAOB. Attempts will be made to identify any metabolites. Further clarification on metabolism and binding will be obtained by conducting in vitro experiments that will include cell free as well as cell culture systems. Findings from the above studies will also be utilized for the understanding of the specific mechanisms by which 2,3,7,8-tetrachlorodibenzo-rho-dioxin (TCDD) causes pathological alterations in mammalian tissues.